Review and experimental verification of x-ray dark-field signal interpretations with respect to quantitative isotropic and anisotropic dark-field computed tomography
| Autor: | Jonas Graetz, Randolf Hanke, Simon Zabler, Andreas Balles |
|---|---|
| Přispěvatelé: | Publica |
| Rok vydání: | 2020 |
| Předmět: |
anisotropic dark-field
FOS: Physical sciences Applied Physics (physics.app-ph) 030218 nuclear medicine & medical imaging 03 medical and health sciences 0302 clinical medicine Optics Scattering Small Angle Humans Radiology Nuclear Medicine and imaging Anisotropy Physics talbot interferometry dark-field signal origination Tomographic reconstruction Radiological and Ultrasound Technology Orientation (computer vision) business.industry Autocorrelation Isotropy computed tomography Observable Signal Processing Computer-Assisted Physics - Applied Physics Physics - Medical Physics ultra small angle scattering Dark field microscopy 030220 oncology & carcinogenesis Medical Physics (physics.med-ph) Small-angle scattering business Tomography X-Ray Computed dark-field imaging |
| Zdroj: | 'Physics in Medicine and Biology ', vol: 65, pages: 235017-1-235017-23 (2020) |
| ISSN: | 1361-6560 0031-9155 |
| Popis: | Talbot(-Lau) interferometric X-ray darkfield imaging has, over the past decade, gained substantial interest for its ability to provide insights into a sample's microstructure below the imaging resolution by means of ultra small angle scattering effects. Quantitative interpretations of such images depend on models of the signal origination process that relate the observable image contrast to underlying physical processes. A review of such models is given here and their relation to the wave optical derivations by Yashiro et al. and Lynch et al. as well as to small angle X-ray scattering is discussed. Fresnel scaling is introduced to explain the characteristic distance dependence observed in cone beam geometries. Moreover, a model describing the anisotropic signals of fibrous objects is derived. The Yashiro-Lynch model is experimentally verified both in radiographic and tomographic imaging in a monochromatic synchrotron setting, considering both the effects of material and positional dependence of the resulting darkfield contrast. The effect of varying sample-detector distance on the darkfield signal is shown to be non-negligible for tomographic imaging, yet can be largely compensated for by symmetric acquisition trajectories. The derived orientation dependence of the darkfield contrast of fibrous materials both with respect to variations in autocorrelation width and scattering cross section is experimentally validated using carbon fiber reinforced rods. Preprint of dissertation chapter to be submitted for publication |
| Databáze: | OpenAIRE |
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